Nick Clegg's political powerbase of Sheffield is among the prizes being eyed up by Labour as it seeks a resurgence in local elections on May 5.

Hundreds of seats are expected to change hands - mainly to Labour's advantage - when voters choose councillors in 279 authorities in most parts of England outside of London.

When the same set of elected positions were last contested, in May 2007, the then governing party was at a very low ebb, trailing the Tories by 13 percentage points in a BBC survey.

David Cameron's party gained more than 900 seats as Labour lost more than 500.

A reduction in the number of councils and seats means Labour probably needs nearer 400 gains to reverse those losses - taking it close to the 7.3% Conservative 2010 General Election margin.

If it pushed the seats advance to 1,000 this would indicate a lead for the party.

But if the sweeping spending cuts generated enough Government unpopularity to take the gains total to 2,000, Labour could be ahead by about 20%.

That would be in line with its last 1995 peak in the dying years of John Major's Tory government.

The one crumb of comfort for ministers in that nightmare scenario would be that in 123 of the 279 councils involved - including the 36 metropolitan authorities covering the big conurbations - only a third of the seats are at stake. And many of the councils where all the seats are up for election are in rural or small town areas where Labour is traditionally weak.

In more than 70 full council contests the two main contending parties are Tories and Lib Dems. In some others the main challenge comes from independents.

Much will depend on the size of the widely forecast Lib Dem seats slump. There are suggestions that it could top 1,000 losses - more than half the seats they are defending.

This may be an exaggeration. In council by-elections since the General Election they have just held their own, offsetting losses to Labour with gains from Tory coalition partners.

If Labour is ahead nationwide it would have hopes of taking Sheffield - where Mr Clegg has his Commons seat - from no overall control and nearby Chesterfield - where it made a surprise General Election gain - from Liberal Democrats.

Metro targets for Labour include Bolton, Leeds and Oldham.

It would also have hopes of capturing Thurrock among the unitary authorities and Ipswich in the non-metropolitan districts.

Tory losses could include Walsall, one of their few metros, and Gedling, in a Labour marginal constituency they failed to win in the General Election.

Other vulnerable Conservative districts include High Peak, Maidstone, Mid Suffolk, Rossendale and Stroud.

They also face losing North Devon to the Lib Dems but might in turn take Lewes from their coalition Government partners.

Among the unitaries Tories may gain Bath and North East Somerset from no overall control.

But Lib Dems might also have hopes of that council, in addition to Mendip, Mid Sussex and Taunton Deane.